// SPDX-License-Identifier: GPL-2.0
#include <stdio.h>
#include <fcntl.h>
#include <libelf.h>
#include <gelf.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <stdbool.h>
#include <stdlib.h>
#include <linux/bpf.h>
#include <linux/perf_event.h>
#include <sys/ioctl.h>
#include <ctype.h>
#include <assert.h>
#include <bpf/bpf.h>
#include "bpf_load.h"
#include "perf-sys.h"

static char license[128];
static int kern_version;
static bool processed_sec[128];

char bpf_log_buf[BPF_LOG_BUF_SIZE];
int map_fd[MAX_MAPS];
int prog_fd[MAX_PROGS];
int event_fd[MAX_PROGS];
int prog_cnt;
int prog_array_fd = -1;

struct bpf_map_data map_data[MAX_MAPS];

int map_data_count;

static inline __u64 ptr_to_u64(const void *ptr) {
    return (__u64) (unsigned long) ptr;
}

struct bpf_create_map_attr {
    const char *name;
    enum bpf_map_type map_type;
    __u32 map_flags;
    __u32 key_size;
    __u32 value_size;
    __u32 max_entries;
    __u32 numa_node;
    __u32 btf_fd;
    __u32 btf_key_type_id;
    __u32 btf_value_type_id;
    __u32 map_ifindex;
    union {
        __u32 inner_map_fd;
        __u32 btf_vmlinux_value_type_id;
    };
};

struct bpf_load_program_attr {
    enum bpf_prog_type prog_type;
    enum bpf_attach_type expected_attach_type;
    const char *name;
    const struct bpf_insn *insns;
    size_t insns_cnt;
    const char *license;
    union {
        __u32 kern_version;
        __u32 attach_prog_fd;
    };
    union {
        __u32 prog_ifindex;
        __u32 attach_btf_id;
    };
    __u32 prog_btf_fd;
    __u32 func_info_rec_size;
    const void *func_info;
    __u32 func_info_cnt;
    __u32 line_info_rec_size;
    const void *line_info;
    __u32 line_info_cnt;
    __u32 log_level;
    __u32 prog_flags;
};

static inline int sys_bpf_prog_load(union bpf_attr *attr, unsigned int size) {
    int fd;

    do {
        fd = sys_bpf(BPF_PROG_LOAD, attr, size);
    } while (fd < 0 && errno == EAGAIN);

    return fd;
}

static void *alloc_zero_tailing_info(const void *orecord, __u32 cnt,
                                     __u32 actual_rec_size, __u32 expected_rec_size) {
    __u64 info_len = (__u64) actual_rec_size * cnt;
    void *info, *nrecord;
    int i;

    info = malloc(info_len);
    if (!info)
        return NULL;

    /* zero out bytes kernel does not understand */
    nrecord = info;
    for (i = 0; i < cnt; i++) {
        memcpy(nrecord, orecord, expected_rec_size);
        memset(nrecord + expected_rec_size, 0,
               actual_rec_size - expected_rec_size);
        orecord += actual_rec_size;
        nrecord += actual_rec_size;
    }

    return info;
}

static int bpf_create_map_in_map_node(enum bpf_map_type map_type, const char *name,
                               int key_size, int inner_map_fd, int max_entries,
                               __u32 map_flags, int node) {
    union bpf_attr attr;

    memset(&attr, '\0', sizeof(attr));

    attr.map_type = map_type;
    attr.key_size = key_size;
    attr.value_size = 4;
    attr.inner_map_fd = inner_map_fd;
    attr.max_entries = max_entries;
    attr.map_flags = map_flags;
    if (name)
        memcpy(attr.map_name, name, min(strlen(name), BPF_OBJ_NAME_LEN - 1));

    if (node >= 0) {
        attr.map_flags |= BPF_F_NUMA_NODE;
        attr.numa_node = node;
    }

    return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
}

static int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr) {
    union bpf_attr attr;

    memset(&attr, '\0', sizeof(attr));

    attr.map_type = create_attr->map_type;
    attr.key_size = create_attr->key_size;
    attr.value_size = create_attr->value_size;
    attr.max_entries = create_attr->max_entries;
    attr.map_flags = create_attr->map_flags;
    if (create_attr->name)
        memcpy(attr.map_name, create_attr->name, min(strlen(create_attr->name), BPF_OBJ_NAME_LEN - 1));
    attr.numa_node = create_attr->numa_node;
    attr.btf_fd = create_attr->btf_fd;
    attr.btf_key_type_id = create_attr->btf_key_type_id;
    attr.btf_value_type_id = create_attr->btf_value_type_id;
    attr.map_ifindex = create_attr->map_ifindex;
    if (attr.map_type == BPF_MAP_TYPE_STRUCT_OPS)
        attr.btf_vmlinux_value_type_id =
                create_attr->btf_vmlinux_value_type_id;
    else
        attr.inner_map_fd = create_attr->inner_map_fd;

    return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
}

static int bpf_create_map_node(enum bpf_map_type map_type, const char *name,
                        int key_size, int value_size, int max_entries,
                        __u32 map_flags, int node) {
    struct bpf_create_map_attr map_attr = {};

    map_attr.name = name;
    map_attr.map_type = map_type;
    map_attr.map_flags = map_flags;
    map_attr.key_size = key_size;
    map_attr.value_size = value_size;
    map_attr.max_entries = max_entries;
    if (node >= 0) {
        map_attr.numa_node = node;
        map_attr.map_flags |= BPF_F_NUMA_NODE;
    }

    return bpf_create_map_xattr(&map_attr);
}

static int bpf_load_program_xattr(const struct bpf_load_program_attr *load_attr,
                           char *log_buf, size_t log_buf_sz) {
    void *finfo = NULL, *linfo = NULL;
    union bpf_attr attr;
    __u32 log_level;
    int fd;

    if (!load_attr || !log_buf != !log_buf_sz)
        return -EINVAL;

    log_level = load_attr->log_level;
    if (log_level > (4 | 2 | 1) || (log_level && !log_buf))
        return -EINVAL;

    memset(&attr, 0, sizeof(attr));
    attr.prog_type = load_attr->prog_type;
    attr.expected_attach_type = load_attr->expected_attach_type;
    if (attr.prog_type == BPF_PROG_TYPE_STRUCT_OPS ||
        attr.prog_type == BPF_PROG_TYPE_LSM) {
        attr.attach_btf_id = load_attr->attach_btf_id;
    } else if (attr.prog_type == BPF_PROG_TYPE_TRACING ||
               attr.prog_type == BPF_PROG_TYPE_EXT) {
        attr.attach_btf_id = load_attr->attach_btf_id;
        attr.attach_prog_fd = load_attr->attach_prog_fd;
    } else {
        attr.prog_ifindex = load_attr->prog_ifindex;
        attr.kern_version = load_attr->kern_version;
    }
    attr.insn_cnt = (__u32) load_attr->insns_cnt;
    attr.insns = ptr_to_u64(load_attr->insns);
    attr.license = ptr_to_u64(load_attr->license);

    attr.log_level = log_level;
    if (log_level) {
        attr.log_buf = ptr_to_u64(log_buf);
        attr.log_size = log_buf_sz;
    } else {
        attr.log_buf = ptr_to_u64(NULL);
        attr.log_size = 0;
    }

    attr.prog_btf_fd = load_attr->prog_btf_fd;
    attr.func_info_rec_size = load_attr->func_info_rec_size;
    attr.func_info_cnt = load_attr->func_info_cnt;
    attr.func_info = ptr_to_u64(load_attr->func_info);
    attr.line_info_rec_size = load_attr->line_info_rec_size;
    attr.line_info_cnt = load_attr->line_info_cnt;
    attr.line_info = ptr_to_u64(load_attr->line_info);
    if (load_attr->name)
        memcpy(attr.prog_name, load_attr->name,
                min(strlen(load_attr->name), BPF_OBJ_NAME_LEN - 1));
    attr.prog_flags = load_attr->prog_flags;

    fd = sys_bpf_prog_load(&attr, sizeof(attr));
    if (fd >= 0)
        return fd;

    /* After bpf_prog_load, the kernel may modify certain attributes
     * to give user space a hint how to deal with loading failure.
     * Check to see whether we can make some changes and load again.
     */
    while (errno == E2BIG && (!finfo || !linfo)) {
        if (!finfo && attr.func_info_cnt &&
            attr.func_info_rec_size < load_attr->func_info_rec_size) {
            /* try with corrected func info records */
            finfo = alloc_zero_tailing_info(load_attr->func_info,
                                            load_attr->func_info_cnt,
                                            load_attr->func_info_rec_size,
                                            attr.func_info_rec_size);
            if (!finfo)
                goto done;

            attr.func_info = ptr_to_u64(finfo);
            attr.func_info_rec_size = load_attr->func_info_rec_size;
        } else if (!linfo && attr.line_info_cnt &&
                   attr.line_info_rec_size <
                   load_attr->line_info_rec_size) {
            linfo = alloc_zero_tailing_info(load_attr->line_info,
                                            load_attr->line_info_cnt,
                                            load_attr->line_info_rec_size,
                                            attr.line_info_rec_size);
            if (!linfo)
                goto done;

            attr.line_info = ptr_to_u64(linfo);
            attr.line_info_rec_size = load_attr->line_info_rec_size;
        } else {
            break;
        }

        fd = sys_bpf_prog_load(&attr, sizeof(attr));

        if (fd >= 0)
            goto done;
    }

    if (log_level || !log_buf)
        goto done;

    /* Try again with log */
    attr.log_buf = ptr_to_u64(log_buf);
    attr.log_size = log_buf_sz;
    attr.log_level = 1;
    log_buf[0] = 0;
    fd = sys_bpf_prog_load(&attr, sizeof(attr));

done:
    free(finfo);
    free(linfo);
    return fd;
}

static int bpf_load_program(enum bpf_prog_type type, const struct bpf_insn *insns,
                     size_t insns_cnt, const char *license,
                     __u32 kern_version, char *log_buf,
                     size_t log_buf_sz) {
    struct bpf_load_program_attr load_attr;

    memset(&load_attr, 0, sizeof(struct bpf_load_program_attr));
    load_attr.prog_type = type;
    load_attr.expected_attach_type = 0;
    load_attr.name = NULL;
    load_attr.insns = insns;
    load_attr.insns_cnt = insns_cnt;
    load_attr.license = license;
    load_attr.kern_version = kern_version;

    return bpf_load_program_xattr(&load_attr, log_buf, log_buf_sz);
}

static int populate_prog_array(const char *event, int prog_fd) {
    int ind = atoi(event), err;

    err = bpf_map_update_elem(prog_array_fd, &ind, &prog_fd, BPF_ANY);
    if (err < 0) {
        printf("failed to store prog_fd in prog_array\n");
        return -1;
    }
    return 0;
}

static int write_kprobe_events(const char *val) {
    int fd, ret, flags;

    if (val == NULL)
        return -1;
    else if (val[0] == '\0')
        flags = O_WRONLY | O_TRUNC;
    else
        flags = O_WRONLY | O_APPEND;

    fd = open(DEBUGFS "kprobe_events", flags);

    ret = write(fd, val, strlen(val));
    close(fd);

    return ret;
}

static int load_and_attach(const char *event, struct bpf_insn *prog, int size) {
    bool is_socket = strncmp(event, "socket", 6) == 0;
    bool is_kprobe = strncmp(event, "kprobe/", 7) == 0;
    bool is_kretprobe = strncmp(event, "kretprobe/", 10) == 0;
    bool is_tracepoint = strncmp(event, "tracepoint/", 11) == 0;
    bool is_raw_tracepoint = strncmp(event, "raw_tracepoint/", 15) == 0;
    bool is_xdp = strncmp(event, "xdp", 3) == 0;
    bool is_perf_event = strncmp(event, "perf_event", 10) == 0;
    bool is_cgroup_skb = strncmp(event, "cgroup/skb", 10) == 0;
    bool is_cgroup_sk = strncmp(event, "cgroup/sock", 11) == 0;
    bool is_sockops = strncmp(event, "sockops", 7) == 0;
    bool is_sk_skb = strncmp(event, "sk_skb", 6) == 0;
    bool is_sk_msg = strncmp(event, "sk_msg", 6) == 0;
    size_t insns_cnt = size / sizeof(struct bpf_insn);
    enum bpf_prog_type prog_type;
    char buf[256];
    int fd, efd, err, id;
    struct perf_event_attr attr = {};

    attr.type = PERF_TYPE_TRACEPOINT;
    attr.sample_type = PERF_SAMPLE_RAW;
    attr.sample_period = 1;
    attr.wakeup_events = 1;

    if (is_socket) {
        prog_type = BPF_PROG_TYPE_SOCKET_FILTER;
    } else if (is_kprobe || is_kretprobe) {
        prog_type = BPF_PROG_TYPE_KPROBE;
    } else if (is_tracepoint) {
        prog_type = BPF_PROG_TYPE_TRACEPOINT;
    } else if (is_raw_tracepoint) {
        prog_type = BPF_PROG_TYPE_RAW_TRACEPOINT;
    } else if (is_xdp) {
        prog_type = BPF_PROG_TYPE_XDP;
    } else if (is_perf_event) {
        prog_type = BPF_PROG_TYPE_PERF_EVENT;
    } else if (is_cgroup_skb) {
        prog_type = BPF_PROG_TYPE_CGROUP_SKB;
    } else if (is_cgroup_sk) {
        prog_type = BPF_PROG_TYPE_CGROUP_SOCK;
    } else if (is_sockops) {
        prog_type = BPF_PROG_TYPE_SOCK_OPS;
    } else if (is_sk_skb) {
        prog_type = BPF_PROG_TYPE_SK_SKB;
    } else if (is_sk_msg) {
        prog_type = BPF_PROG_TYPE_SK_MSG;
    } else {
        printf("Unknown event '%s'\n", event);
        return -1;
    }

    if (prog_cnt == MAX_PROGS)
        return -1;

    fd = bpf_load_program(prog_type, prog, insns_cnt, license, kern_version,
                          bpf_log_buf, BPF_LOG_BUF_SIZE);
    if (fd < 0) {
        printf("bpf_load_program() err=%d\n%s", errno, bpf_log_buf);
        return -1;
    }

    prog_fd[prog_cnt++] = fd;

    if (is_xdp || is_perf_event || is_cgroup_skb || is_cgroup_sk)
        return 0;

    if (is_socket || is_sockops || is_sk_skb || is_sk_msg) {
        if (is_socket)
            event += 6;
        else
            event += 7;
        if (*event != '/')
            return 0;
        event++;
        if (!isdigit(*event)) {
            printf("invalid prog number\n");
            return -1;
        }
        return populate_prog_array(event, fd);
    }

    if (is_raw_tracepoint) {
        efd = bpf_raw_tracepoint_open(event + 15, fd);
        if (efd < 0) {
            printf("tracepoint %s %s\n", event + 15, strerror(errno));
            return -1;
        }
        event_fd[prog_cnt - 1] = efd;
        return 0;
    }

    if (is_kprobe || is_kretprobe) {
        bool need_normal_check = true;
        const char *event_prefix = "";

        if (is_kprobe)
            event += 7;
        else
            event += 10;

        if (*event == 0) {
            printf("event name cannot be empty\n");
            return -1;
        }

        if (isdigit(*event))
            return populate_prog_array(event, fd);

#ifdef __x86_64__
        if (strncmp(event, "sys_", 4) == 0) {
            snprintf(buf, sizeof(buf), "%c:__x64_%s __x64_%s",
                     is_kprobe ? 'p' : 'r', event, event);
            err = write_kprobe_events(buf);
            if (err >= 0) {
                need_normal_check = false;
                event_prefix = "__x64_";
            }
        }
#endif
        if (need_normal_check) {
            snprintf(buf, sizeof(buf), "%c:%s %s",
                     is_kprobe ? 'p' : 'r', event, event);
            err = write_kprobe_events(buf);
            if (err < 0) {
                printf("failed to create kprobe '%s' error '%s'\n",
                       event, strerror(errno));
                return -1;
            }
        }

        strcpy(buf, DEBUGFS);
        strcat(buf, "events/kprobes/");
        strcat(buf, event_prefix);
        strcat(buf, event);
        strcat(buf, "/id");
    } else if (is_tracepoint) {
        event += 11;

        if (*event == 0) {
            printf("event name cannot be empty\n");
            return -1;
        }
        strcpy(buf, DEBUGFS);
        strcat(buf, "events/");
        strcat(buf, event);
        strcat(buf, "/id");
    }

    efd = open(buf, O_RDONLY, 0);
    if (efd < 0) {
        printf("failed to open event %s\n", event);
        return -1;
    }

    err = read(efd, buf, sizeof(buf));
    if (err < 0 || err >= sizeof(buf)) {
        printf("read from '%s' failed '%s'\n", event, strerror(errno));
        return -1;
    }

    close(efd);

    buf[err] = 0;
    id = atoi(buf);
    attr.config = id;

    efd = sys_perf_event_open(&attr, -1/*pid*/, 0/*cpu*/, -1/*group_fd*/, 0);
    if (efd < 0) {
        printf("event %d fd %d err %s\n", id, efd, strerror(errno));
        return -1;
    }
    event_fd[prog_cnt - 1] = efd;
    err = ioctl(efd, PERF_EVENT_IOC_ENABLE, 0);
    if (err < 0) {
        printf("ioctl PERF_EVENT_IOC_ENABLE failed err %s\n",
               strerror(errno));
        return -1;
    }
    err = ioctl(efd, PERF_EVENT_IOC_SET_BPF, fd);
    if (err < 0) {
        printf("ioctl PERF_EVENT_IOC_SET_BPF failed err %s\n",
               strerror(errno));
        return -1;
    }

    return 0;
}

static int load_maps(struct bpf_map_data *maps, int nr_maps,
                     fixup_map_cb fixup_map) {
    int i, numa_node;

    for (i = 0; i < nr_maps; i++) {
        if (fixup_map) {
            fixup_map(&maps[i], i);
            /* Allow userspace to assign map FD prior to creation */
            if (maps[i].fd != -1) {
                map_fd[i] = maps[i].fd;
                continue;
            }
        }

        numa_node = maps[i].def.map_flags & BPF_F_NUMA_NODE ?
                    maps[i].def.numa_node : -1;

        if (maps[i].def.type == BPF_MAP_TYPE_ARRAY_OF_MAPS ||
            maps[i].def.type == BPF_MAP_TYPE_HASH_OF_MAPS) {
            int inner_map_fd = map_fd[maps[i].def.inner_map_idx];

            map_fd[i] = bpf_create_map_in_map_node(maps[i].def.type,
                                                   maps[i].name,
                                                   maps[i].def.key_size,
                                                   inner_map_fd,
                                                   maps[i].def.max_entries,
                                                   maps[i].def.map_flags,
                                                   numa_node);
        } else {
            map_fd[i] = bpf_create_map_node(maps[i].def.type,
                                            maps[i].name,
                                            maps[i].def.key_size,
                                            maps[i].def.value_size,
                                            maps[i].def.max_entries,
                                            maps[i].def.map_flags,
                                            numa_node);
        }
        if (map_fd[i] < 0) {
            printf("failed to create map %d (%s): %d %s\n",
                   i, maps[i].name, errno, strerror(errno));
            return 1;
        }
        maps[i].fd = map_fd[i];

        if (maps[i].def.type == BPF_MAP_TYPE_PROG_ARRAY)
            prog_array_fd = map_fd[i];
    }
    return 0;
}

static int get_sec(Elf *elf, int i, GElf_Ehdr *ehdr, char **shname,
                   GElf_Shdr *shdr, Elf_Data **data) {
    Elf_Scn *scn;

    scn = elf_getscn(elf, i);
    if (!scn)
        return 1;

    if (gelf_getshdr(scn, shdr) != shdr)
        return 2;

    *shname = elf_strptr(elf, ehdr->e_shstrndx, shdr->sh_name);
    if (!*shname || !shdr->sh_size)
        return 3;

    *data = elf_getdata(scn, 0);
    if (!*data || elf_getdata(scn, *data) != NULL)
        return 4;

    return 0;
}

static int parse_relo_and_apply(Elf_Data *data, Elf_Data *symbols,
                                GElf_Shdr *shdr, struct bpf_insn *insn,
                                struct bpf_map_data *maps, int nr_maps) {
    int i, nrels;

    nrels = shdr->sh_size / shdr->sh_entsize;

    for (i = 0; i < nrels; i++) {
        GElf_Sym sym;
        GElf_Rel rel;
        unsigned int insn_idx;
        bool match = false;
        int map_idx;

        gelf_getrel(data, i, &rel);

        insn_idx = rel.r_offset / sizeof(struct bpf_insn);

        gelf_getsym(symbols, GELF_R_SYM(rel.r_info), &sym);

        if (insn[insn_idx].code != (BPF_LD | BPF_IMM | BPF_DW)) {
            printf("invalid relo for insn[%d].code 0x%x\n",
                   insn_idx, insn[insn_idx].code);
            return 1;
        }
        insn[insn_idx].src_reg = BPF_PSEUDO_MAP_FD;

        /* Match FD relocation against recorded map_data[] offset */
        for (map_idx = 0; map_idx < nr_maps; map_idx++) {
            if (maps[map_idx].elf_offset == sym.st_value) {
                match = true;
                break;
            }
        }
        if (match) {
            insn[insn_idx].imm = maps[map_idx].fd;
        } else {
            printf("invalid relo for insn[%d] no map_data match\n",
                   insn_idx);
            return 1;
        }
    }

    return 0;
}

static int cmp_symbols(const void *l, const void *r) {
    const GElf_Sym *lsym = (const GElf_Sym *) l;
    const GElf_Sym *rsym = (const GElf_Sym *) r;

    if (lsym->st_value < rsym->st_value)
        return -1;
    else if (lsym->st_value > rsym->st_value)
        return 1;
    else
        return 0;
}

static int load_elf_maps_section(struct bpf_map_data *maps, int maps_shndx,
                                 Elf *elf, Elf_Data *symbols, int strtabidx) {
    int map_sz_elf, map_sz_copy;
    bool validate_zero = false;
    Elf_Data *data_maps;
    int i, nr_maps;
    GElf_Sym *sym;
    Elf_Scn *scn;
    // int copy_sz;

    if (maps_shndx < 0)
        return -EINVAL;
    if (!symbols)
        return -EINVAL;

    /* Get data for maps section via elf index */
    scn = elf_getscn(elf, maps_shndx);
    if (scn)
        data_maps = elf_getdata(scn, NULL);
    if (!scn || !data_maps) {
        printf("Failed to get Elf_Data from maps section %d\n",
               maps_shndx);
        return -EINVAL;
    }

    /* For each map get corrosponding symbol table entry */
    sym = calloc(MAX_MAPS + 1, sizeof(GElf_Sym));
    for (i = 0, nr_maps = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
        assert(nr_maps < MAX_MAPS + 1);
        if (!gelf_getsym(symbols, i, &sym[nr_maps]))
            continue;
        if (sym[nr_maps].st_shndx != maps_shndx)
            continue;
        /* Only increment iif maps section */
        nr_maps++;
    }

    /* Align to map_fd[] order, via sort on offset in sym.st_value */
    qsort(sym, nr_maps, sizeof(GElf_Sym), cmp_symbols);

    /* Keeping compatible with ELF maps section changes
     * ------------------------------------------------
     * The program size of struct bpf_load_map_def is known by loader
     * code, but struct stored in ELF file can be different.
     *
     * Unfortunately sym[i].st_size is zero.  To calculate the
     * struct size stored in the ELF file, assume all struct have
     * the same size, and simply divide with number of map
     * symbols.
     */
    map_sz_elf = data_maps->d_size / nr_maps;
    map_sz_copy = sizeof(struct bpf_load_map_def);
    if (map_sz_elf < map_sz_copy) {
        /*
         * Backward compat, loading older ELF file with
         * smaller struct, keeping remaining bytes zero.
         */
        map_sz_copy = map_sz_elf;
    } else if (map_sz_elf > map_sz_copy) {
        /*
         * Forward compat, loading newer ELF file with larger
         * struct with unknown features. Assume zero means
         * feature not used.  Thus, validate rest of struct
         * data is zero.
         */
        validate_zero = true;
    }

    /* Memcpy relevant part of ELF maps data to loader maps */
    for (i = 0; i < nr_maps; i++) {
        struct bpf_load_map_def *def;
        unsigned char *addr, *end;
        const char *map_name;
        size_t offset;

        map_name = elf_strptr(elf, strtabidx, sym[i].st_name);
        maps[i].name = strdup(map_name);
        if (!maps[i].name) {
            printf("strdup(%s): %s(%d)\n", map_name,
                   strerror(errno), errno);
            free(sym);
            return -errno;
        }

        /* Symbol value is offset into ELF maps section data area */
        offset = sym[i].st_value;
        def = (struct bpf_load_map_def *) (data_maps->d_buf + offset);
        maps[i].elf_offset = offset;
        memset(&maps[i].def, 0, sizeof(struct bpf_load_map_def));
        memcpy(&maps[i].def, def, map_sz_copy);

        /* Verify no newer features were requested */
        if (validate_zero) {
            addr = (unsigned char *) def + map_sz_copy;
            end = (unsigned char *) def + map_sz_elf;
            for (; addr < end; addr++) {
                if (*addr != 0) {
                    free(sym);
                    return -EFBIG;
                }
            }
        }
    }

    free(sym);
    return nr_maps;
}

static int do_load_bpf_file(const char *path, fixup_map_cb fixup_map) {
    int fd, i, ret, maps_shndx = -1, strtabidx = -1;
    Elf *elf;
    GElf_Ehdr ehdr;
    GElf_Shdr shdr, shdr_prog;
    Elf_Data *data, *data_prog, *data_maps = NULL, *symbols = NULL;
    char *shname, *shname_prog;
    int nr_maps = 0;

    /* reset global variables */
    kern_version = 0;
    memset(license, 0, sizeof(license));
    memset(processed_sec, 0, sizeof(processed_sec));

    if (elf_version(EV_CURRENT) == EV_NONE)
        return 1;

    fd = open(path, O_RDONLY, 0);
    if (fd < 0)
        return 1;

    elf = elf_begin(fd, ELF_C_READ, NULL);

    if (!elf)
        return 1;

    if (gelf_getehdr(elf, &ehdr) != &ehdr)
        return 1;

    /* clear all kprobes */
    i = write_kprobe_events("");

    /* scan over all elf sections to get license and map info */
    for (i = 1; i < ehdr.e_shnum; i++) {

        if (get_sec(elf, i, &ehdr, &shname, &shdr, &data))
            continue;

        if (1) {
            /* helpful for llvm debugging */
            printf("section %d:%s data %p size %zd link %d flags %d\n",
                   i, shname, data->d_buf, data->d_size,
                   shdr.sh_link, (int) shdr.sh_flags);
        }

        if (strcmp(shname, "license") == 0) {
            processed_sec[i] = true;
            memcpy(license, data->d_buf, data->d_size);
        } else if (strcmp(shname, "version") == 0) {
            processed_sec[i] = true;
            if (data->d_size != sizeof(int)) {
                printf("invalid size of version section %zd\n",
                       data->d_size);
                return 1;
            }
            memcpy(&kern_version, data->d_buf, sizeof(int));
        } else if (strcmp(shname, "maps") == 0) {
            int j;

            maps_shndx = i;
            data_maps = data;
            for (j = 0; j < MAX_MAPS; j++)
                map_data[j].fd = -1;
        } else if (shdr.sh_type == SHT_SYMTAB) {
            strtabidx = shdr.sh_link;
            symbols = data;
        }
    }

    ret = 1;

    if (!symbols) {
        printf("missing SHT_SYMTAB section\n");
        goto done;
    }

    if (data_maps) {
        nr_maps = load_elf_maps_section(map_data, maps_shndx,
                                        elf, symbols, strtabidx);
        if (nr_maps < 0) {
            printf("Error: Failed loading ELF maps (errno:%d):%s\n",
                   nr_maps, strerror(-nr_maps));
            goto done;
        }
        if (load_maps(map_data, nr_maps, fixup_map))
            goto done;
        map_data_count = nr_maps;

        processed_sec[maps_shndx] = true;
    }

    /* process all relo sections, and rewrite bpf insns for maps */
    for (i = 1; i < ehdr.e_shnum; i++) {
        if (processed_sec[i])
            continue;

        if (get_sec(elf, i, &ehdr, &shname, &shdr, &data))
            continue;

        if (shdr.sh_type == SHT_REL) {
            struct bpf_insn *insns;

            /* locate prog sec that need map fixup (relocations) */
            if (get_sec(elf, shdr.sh_info, &ehdr, &shname_prog,
                        &shdr_prog, &data_prog))
                continue;

            if (shdr_prog.sh_type != SHT_PROGBITS ||
                !(shdr_prog.sh_flags & SHF_EXECINSTR))
                continue;

            insns = (struct bpf_insn *) data_prog->d_buf;
            processed_sec[i] = true; /* relo section */

            if (parse_relo_and_apply(data, symbols, &shdr, insns,
                                     map_data, nr_maps))
                continue;
        }
    }

    /* load programs */
    for (i = 1; i < ehdr.e_shnum; i++) {

        if (processed_sec[i])
            continue;

        if (get_sec(elf, i, &ehdr, &shname, &shdr, &data))
            continue;

        if (memcmp(shname, "kprobe/", 7) == 0 ||
            memcmp(shname, "kretprobe/", 10) == 0 ||
            memcmp(shname, "tracepoint/", 11) == 0 ||
            memcmp(shname, "raw_tracepoint/", 15) == 0 ||
            memcmp(shname, "xdp", 3) == 0 ||
            memcmp(shname, "perf_event", 10) == 0 ||
            memcmp(shname, "socket", 6) == 0 ||
            memcmp(shname, "cgroup/", 7) == 0 ||
            memcmp(shname, "sockops", 7) == 0 ||
            memcmp(shname, "sk_skb", 6) == 0 ||
            memcmp(shname, "sk_msg", 6) == 0) {
            ret = load_and_attach(shname, data->d_buf,
                                  data->d_size);
            if (ret != 0)
                goto done;
        }
    }

done:
    close(fd);
    return ret;
}

int load_bpf_file(char *path) {
    return do_load_bpf_file(path, NULL);
}

int load_bpf_file_fixup_map(const char *path, fixup_map_cb fixup_map) {
    return do_load_bpf_file(path, fixup_map);
}
